PROJECT SUMMARY Current strategies for cardiac safety evaluation of drugs have shown significant limitations. Over the past several years, the FDA and pharmaceutical industry have promoted initiatives to develop more predictive human-relevant preclinical platforms to rectify this problem. In this context, AnaBios established an adult human primary cardiomyocyte contractility model, which has the potential to predict drug-induced pro- arrhythmia risk. The correlation between electrical (action potential, AP) and mechanical (contraction) abnormalities, is a consequence of the tight functional coupling between these two processes in adult cardiac cells and tissues. As a result, drug-induced ventricular repolarization irregularities also lead to severe contractility abnormalities. In line with these observations, AnaBios has developed an adult human primary ventricular cardiomyocyte contractility model that simultaneously evaluates pro-arrhythmia risks from the measurement of drug-induced changes in several parameters that are derived from the kinetics of the contractility transient; AnaBios is further combining the parameters into a single biomarker that can be used to predict pro-arrhythmia risk in advance of clinical studies. AnaBios aims to qualify the biomarker derived from the contractility measurements, which will provide critical information for drug developers and regulators with respect to the cardiac risk of drugs at the preclinical stages of drug development.